A system of capturing waste heat includes a heat recovery unit (20) having a heat exchanger (35) arranged to transfer heat between a fluid circulating in a refrigerant loop (60) and a fluid circulating in a solar loop (70) and another heat exchanger (39) arranged to transfer heat between the fluid in the solar loop (70) and a fluid circulating in a water loop (50). Controllable first, second, and third three-way valves (V1-V3) provide or prevent, depending on fluid temperatures, an A-B, B-C, and A-C flow path through the valve. The first valve (V1) is arranged in the water loop (50) upstream of the second heat exchanger (39). The second (V2) is arranged in the solar loop (70) upstream of the second heat exchanger (39). The third valve (V3) is arranged in the solar loop (70) between the first and second heat exchangers (35, 39).

The present invention relates to a hot water storage tank (202, 302, 402, 502, 602, 702), defining a primly storage volume (204, 304, 404, 504, 604, 704), with at least one heat source (212, 312, 412, 512, 612, 712) positioned in and operable to directly heat water in the upper portion (207, 307, 407, 507, 607, 707) of the primary storage volume (204, 304, 404, 04, 604, 704), and a pump or other means (237, 337, 437, 537, 637) that draws water, from the lower portion (209, 309, 409, 509, 609, 709) of the tank into a heat transfer device (216, 316, 416, 516, 616, 716), situated in said upper portion (207, 307, 407, 507, 607, 707). The heat transfer device (216, 316, 416, 516, 616, 716) is configured to enable the transfer of heat from heated water in the upper portion (207, 307, 407, 507, 607, 707) to the drawn water prior to discharge into the water in the upper portion (207, 307, 407, 507, 607, 707).

An instant hot water delivery system includes a thermal storage bin that receives hot water from a water heater via a hot water supply conduit and stores the hot water therein. The thermal storage bin is disposed adjacent a point of demand to deliver the hot water instantly to the point of demand responsive to a demand. The thermal storage bin is configured to retain a thermal energy of the hot water for a prolonged period using a phase change material. When the hot water stored in the thermal storage bin cools down below a threshold temperature, the cooled down hot water is recirculated to the water heater via a cold water supply conduit using a crossover valve. The recirculation is based on thermosiphon. Fresh hot water from the water heater replaces the cooled down hot water that is displaced from the thermal storage bin.

A water heater includes a heat exchanger. A controllable three-way proportional valve provides a proportionally controllable flow to the hot water inlet of the heat exchanger and a boiler return water outlet. A mixing tank mixes a cold water and a hot water. The mixing tank provides a time delayed mixed water. A temperature sensor is disposed in or on the mixing tank to measure a temperature of the time delayed mixed water to provide a time delayed mixed water temperature. A feedforward control process running on a processor adjusts a proportional operating position of the controllable three-way proportional valve to regulate a temperature of hot water at the hx domestic hot water outlet based on the temperature of the time delayed mixed water temperature. A method for controlling a hot water temperature of a water heater a water heater using a flowmeter based feedforward control are also described.

According to various aspects of the invention, a cooking system is disclosed. The cooking system includes one or more thermal storages capable of storing thermal energy using electric power received from one or more energy source; one or more heat exchanger circuit for transferring the thermal energy from the one or more thermal storages; and a cooking unit arranged in heat exchanging relationship with the one or more thermal storages via one or more heat exchanger circuits. The cooking unit receives the thermal energy from the one or more thermal storages for cooking

A heat exchanger for an apparatus including a burner has at least one tube extending along a centerline from an inlet end adjacent the burner to an outlet end. A plurality of indentations is formed in the tube adjacent the inlet end and extend radially inward towards the centerline. The indentations are formed in opposing pairs extending towards one another to a depth sufficient to create turbulent fluid flow through the inlet end of the tube.

The disclosed technology relates to a solar water heating system including a tank configured to store heat transfer fluid, a solar collector in fluid communication with the tank, and a pump system in fluid communication with the tank and the solar collector. The pump system can include a first pump, a second pump, and a valve assembly. The valve assembly can direct the heat transfer fluid from an outlet of the first pump to the solar collector when the first pump is operating and can direct the heat transfer fluid from an outlet of the second pump to the solar collector when the second pump is operating. The first pump and the second pump can transfer the heat transfer fluid from the solar collector back to the tank when the first pump and the second pump are not operating.

A combination boiler provides heated water to a boiler loop and heated domestic hot water (DHW) to a DHW loop. A primary heat exchanger is connected to the boiler loop. A burner provides heat to the primary heat exchanger and an input fan supplies a fuel and air mixture to the burner. A secondary heat exchanger transfers heat energy from the boiler loop to a domestic water loop. A controller determines a boiler loop flow rate. The controller measures an input temperature of the boiler loop, an output temperature of the boiler loop, and a DHW output temperature of the domestic water loop. The controller determines a DHW input temperature and estimates a DHW flow rate. The input fan speed is initiated or operated according to a required heat output of the burner corresponding to the DHW flow rate.

A water heater includes a heat exchanger. A controllable three-way proportional valve provides a proportionally controllable flow to the hot water inlet of the heat exchanger and a boiler return water outlet. A mixing tank mixes a cold water and a hot water. The mixing tank provides a time delayed mixed water. A temperature sensor is disposed in or on the mixing tank to measure a temperature of the time delayed mixed water to provide a time delayed mixed water temperature. A feedforward control process running on a processor adjusts a proportional operating position of the controllable three-way proportional valve to regulate a temperature of hot water at the hx domestic hot water outlet based on the temperature of the time delayed mixed water temperature. A method for controlling a hot water temperature of a water heater a water heater using a flowmeter based feedforward control are also described.

A heating, ventilation, and air conditioning system includes a heating system. The heating system portion of the HVAC unit can comprise an array of heat exchanger tubes attached to a first side of a heat exchanger panel and a burner assembly attached to a second side of the heat exchanger panel. The burner assembly can comprise one or more tabs to facilitate installation and removal of the burner assembly within the HVAC system. The heat exchanger panel can comprise one or more slots that receive the one or more tabs of the burner assembly.